Abstract This review states the outline of field crop production of Japan and weed problems to be solved. Field crop production of Japan is characterized by rice cultivation and small size farming. Most major field crops other than rice are imported, and various kinds and a very large amount of living weed seeds contaminate the imported grains. These alien weeds sometimes invade agricultural fields and cause serious losses of crop yields and reductions in the quality of agricultural products. Emergence of herbicide resistant biotypes of weeds, especially paddy weeds, is also issues to be solved. Weedy rice is recently emerging again due to the change of rice production system and the origin of recently emerging weedy rice is not clarified yet.

中文翻译：

---

日本杂草管理的研究问题、挑战和机遇

摘要 本文概述了日本大田作物生产的概况和需要解决的杂草问题。日本大田作物生产的特点是水稻种植和小规模农业。除水稻外的主要大田作物大部分是进口的，各种种类和数量非常多的活杂草种子污染了进口粮食。这些外来杂草有时会侵入农田，造成农作物产量的严重损失和农产品质量的下降。杂草特别是稻谷杂草抗除草剂生物型的出现也是亟待解决的问题。由于水稻生产体制的变化，最近出现的杂草稻再次出现，而最近出现的杂草稻的来源尚未明确。